直接序列扩频信号的盲检测和参数估计方法

发布时间：2018-05-07 17:34

本文选题：DS-SS信号 + 参数估计　；参考：《北京邮电大学》2008年硕士论文

【摘要】： 由于现代通信技术和检测技术的飞速发展,推动了对通信对抗技术的深入研究。扩频信号作为一种难预测的伪随机、宽带、低电平信号,具有抗干扰性强、截获概率低、可实现码分多址与高精度定时定位等优点,因而被广泛应用于移动通信、雷达、导航(GPS)和测量等多种领域。对直接序列扩频(DS-SS)信号的侦察已引起人们的极大关注,并开展了这方面的研究工作,其中对DS信号及直扩码分多址(DS/CDMA)信号进行盲检测与估计是首要任务。直扩通信信号检测与估计的研究已发展出很多方法,不过这些方法基本都是基于常规信号的检测与估计方法,而直扩信号是宽带微弱信号,不符合常规信号的处理方法,因此当直扩信号的信噪比较低时,这些常规估计方法的估计性能恶化,甚至根本得不到正确的估计结果。从目前的研究发展情况来看,直扩通信信号的估计方法研究进展还比较缓慢,具体估计方法的研究还不够全面成熟。本文的主要工作是在未具有任何先验知识的情况下,对DS-SS信号的参数进行盲检测与估计,主要研究了平方倍频检测、自相关函数检测、高阶累积量检测等方法,进行了详细的理论分析和仿真验证,并提出了一些新的思想和方法。上述三种方法都能完成低信噪比情况下的DS-SS信号检测,各自对信号的某一个参数特征有很好的估计性能。其中平方倍频检测与相关累积技术相结合能够较精确的估计信号的载波频率;自相关函数检测方法利用DS信号的时域特征,将其与二次谱相结合能够完成对准确地提取信号的伪码周期,而其二阶矩又能够很好地估计扩频信号的载频;高阶谱技术是直接序列扩频信号检测的另一途径,其中基于四阶累积量2-D非对角切片的检测方法能够很好地抑制高斯白噪声,并且兼顾了时域相关检测和平方倍频检测两种方法的特点,能够同时估计出扩频码周期和载波频率两个参数。
[Abstract]:With the rapid development of modern communication technology and detection technology, the research of communication countermeasure technology is promoted. As a kind of pseudorandom, wideband and low level signal, spread spectrum signal has the advantages of strong anti-jamming, low probability of interception, and can realize code division multiple access (CDMA) and high precision timing positioning, so it is widely used in mobile communication, radar, etc. Navigation GPS) and measurement and other fields. The detection of direct sequence spread spectrum (DS-SS) signals has attracted much attention and research work has been carried out. Blind detection and estimation of DS signals and DS / CDMA signals is the primary task. Many methods have been developed for the detection and estimation of DSSS communication signals, but these methods are basically based on the detection and estimation of conventional signals, and the DSSS signals are wideband weak signals, which do not conform to the processing methods of conventional signals. Therefore, when the SNR of DSSS signal is low, the estimation performance of these conventional estimation methods is deteriorated, and even the correct estimation results are not obtained at all. According to the current research and development, the research progress of DSSS signal estimation method is still slow, and the research of specific estimation method is not comprehensive and mature enough. The main work of this paper is to detect and estimate the parameters of DS-SS signal without any prior knowledge. The methods of squared double frequency detection, autocorrelation function detection, high order cumulant detection and so on are studied. Detailed theoretical analysis and simulation verification are carried out, and some new ideas and methods are put forward. The above three methods can detect DS-SS signals with low SNR, and each has good estimation performance for a certain parameter feature of the signal. The square double frequency detection combined with the correlation accumulation technique can accurately estimate the carrier frequency of the signal, and the autocorrelation function detection method utilizes the time-domain characteristics of the DS signal. Combining it with quadratic spectrum, the pseudo-code period of accurately extracted signal can be completed, and its second moment can estimate the carrier frequency of spread spectrum signal very well, and high order spectrum technology is another way to detect direct sequence spread spectrum signal. The detection method based on 4-order cumulant 2-D non-diagonal slice can suppress Gao Si white noise very well, and it takes into account the characteristics of time domain correlation detection and square frequency doubling detection. The two parameters of spread code cycle and carrier frequency can be estimated simultaneously.
【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：TN914.42

【引证文献】